[MarsIronPI]

I don't know why there aren't independent X86-64 manufacturers. Patents on the extensions maybe? But as I understand copyright, APIs can't be copyrighted so it's not that.

[panick21_]

The original ARM 32 stuff is clearly out of patents and is not being copied. And it doesn't require new extensions to be commercially viable.

[userbinator]

and is not being copied

Are you sure, especially considering China?

I doubt there is any legal barrier, because there are a few existing projects with x86 cores on an FPGA, as well as some SoCs. Here's a 486: https://opencores.org/projects/ao486

[panick21_]

Ok if China is doing something only for China market that tells you something.

As for opencores, yes you can design them, but do any companies making commercial products sell them?

[sidewndr46]

I'm reasonably certain at least one Chinese fab has a license for some of AMDs older product lines